Do you see any other messages before “Starting Plymouth-quit-wait.service - Hold until boot process finishes up…”?
Is it the same as here?
What GPUs do you have in your machine (integrated and/or dedicated)?
Do you have multiple displays? To what GPU are they connected?
You can try to connect your display to another GPU if you have more than one.
Or you can try to reinstall Qubes OS with kernel-latest, there is a separate Qubes OS installer GRUB menu option for this.